Definition: You are given a math word problem and you are supposed to only use subtraction on the numbers embedded in the text to answer the following question and then only report the final numerical answer.
Input: Context: Danny collects bottle caps and wrappers. He found 82 wrappers and 29 bottle caps at the park. Now he has 42 bottle caps and 61 wrappers in his collection. 

 Question: How many bottle caps did danny have at first?

13